Multirange flow nozzle



foct. 27 1925 C. F. BULLOCK MULTIRANGE FLOW 'NozzLE Filed 06h17. 1924 zsneets-snen 1` Figi..

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Inventor-f.

- Cl'crle ,F Bullock?, l b5 W f His Attorfg,

In-ventor ChcLrLes Ff Bullock @y MJ? I-ILS Attorngy Patented Oct. 27, 11925.

UNITED STATES lPATENT OFFICE.

CHARLES F.,BLLOCK, OF SCHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK.

MULTIRANGE FLOW NOZZLE.

Application led October 17, 1924. Serial No. 744,276.

Y is a specilication.\

In `connection with flowv meters for measuring the flow of fluids through con` duits, there is'used a pressure difference creating device wluch creates a pressure difference' proportlonal to the rate 'of flow,

and this pressure difference ismeasured in order to measure the flow. One form of pressure difference' creating device in use is that known as a fiow nozzle (see the patent lto Dodge, No. 1,298,471, patented March25, 1919) and my invention relatesy particularly to a Lpressure difference creat- ,ing device ot thistype. f

.of a'f'iow tube structure embodying my in- The pressure difference created with a device of' this type varies with the square of the How. lVhen measuring low velocity flow, the pressure difference to be measured maybe quite small, while when measuring high velocity flow the pressure difference may bequite large.

The pressure difference is measured on an instrument of thc U-tube typel containingl anv indicating liquid such as mercury, the

same comprising leading and trailing legs connected across the flow nozzle` thedeliection of the liquid indicating the pressure difference. The deflection measured is usually the deflection. in one leg of the U-tube instrument, and, as is Well known, the amount of the total deflection in this one leg depends upon the relative areas of' the two legs. For different flow conditions, U-tube instruments arev provided wherein the. legs have different relative areas, the relative areas depending upon the total pressuredifference to be handled.- In other words, U-tube instruments having legs of different relative areas are provided for differentpressure difference ranges. An eX- ample of this is well illustrated by the construction shown in the patent to Mapelsden,

No. 1,481,921, Jan. 29, 192i. It. will be understood that the possible length of the logs of a U-tube is limited in actual practice for manufacturing and mechanical reasons.

The object of' the 'present invention is to provide a flow nozzle construction and arrangement whereby substantially the same pressure difference range may be obtained under different How conditions, thereby enabling the same U-tube indicating instrument to be used under widely different How cond-itions. In this connection it lis pointed out that a U-tube indicating instrument for measuring relatively great deflections is not well suited for measuring small deliections because the scale divisions .become small and diiicult to read and in addition, at small deflections such instruments are not very accurate. It is .desirable accordingly, to utilize the total pressure range of the U-tube with the different ow conditions met with. f

For a consideration of what I believe to be novel and my invention, attention is di.- re'cted to the accompanying description and the claims appended thereto.

In the drawing, Fig. 1 is a sectional view vention; Fig. 2 is a sectional view of a modification, and Fig. 3 is a diagram of the flow tube structure shown in Fig. ,1, the

same being shown connected to a U-tube of the type disclosed in the before mentioned Mapelsden patent.

' Referring to the drawing, Figs. 1 and 3, 5 indicates a conduit through which a Huid to be metered flows 'and 6 indicates a pressure difference measuring-'instrument of the U-tube type such as that disclosed in the before mentioned Mapelsden patent. The leading leg 'is indicated at 7, the trailing legat 8 and the indicating liquid at 9. 10 indicates the float'which rides on the indicating liquid and actuates vthe indicating mechanism, such as a pointer, through the rack 1l -and pinion 12. `.This construction is to be taken as typical of any suitable or known indica-ting instrument of the U-tube' type for use in {low meters. In connection with it, it will be noted that the area of leg 8 is `larger than that 0f legf) so that the greater portion of the deflection takes place in leg 9 and also that the deflection in leg 9 is limited to substantially the distances. This means that the U-tube is capable of taking care of a certain pressured-iierence range. i A

-According to my invention, I provide for use with a U-tube-instrument of this type a flow nozzle of special construction and arrangement whereby it is capable of being used to produce the same pressure difference range under different flow conditions. For example, take the caseof a steam fiow meter used for measuring steam for heating purposes. During cold weather a large amount of steam may be required continuously, while during warm weather a smaller amount of steam may be required continuously. v'If a flow meter is used having a pressure difference creating device vadapted for the larger flow coudif tions, then when smaller iiow conditions Aobtain but a small part of the liquid doflection will be utilized and the meter will not give as accurate results as it would were the total liquid deflection utilized. By my invention I am enabled to utilize the total liquid deflection at times of both large flow andsmall iow.

The idea broadly. of a multi-range pressure difference creating device is not new.,

but so far as I am aware in constructions heretofore suggested, it has been necessaryv the construction of my flow nozzlewhereby-I 'am enabled to accomplish this result length to bring the tube to the desired (li.

I regard as being the important feature of my invention.

My improved How nozzle comprises a curved section 13 which faces up stream and merges into a straight section 14 which is of a length equal to at least substantially one-fourth of its diameter and preferably is not longer than its own diameter, the length being lsuch as to straighten the lines of fiowv and render them parallel.` Following this Iprovide a short curved Asection 1'5 having a radius of curvature' equal preferably to at least one pipe-diameter which merges into a straight Haring section 1G, the angle of which is such that it confines the fluid and prevents free expansion. Preferably I utilize 'an angle of not more than 5 degrees. Flari'ng section 16 is of a.

ameter, after which it merges into 4 a straight section 17 of a length equalto at least substantially one-fourth of its own diameter.

The fiow tube is provided witha fla/nge.. is adapted to be clamped between twg ad,v

jacent pipe ends.

With the above .describecY arrangement, I

obtain three definite pressures, the 'pressure in advance of the flow` tube, the pressureln Sectron 14, and the pressure `surrounding the straight section 17, and any combination of two of these pressures may be utilized in measuring ow through conduit 5. To this end conduit 5 in advance of the'flow tube is connected bya pipe 19 to the leading ,leg 7 of the U-tube, the pipe i being provided with avalve 20-; straight section 145 is connectedby a pipe 21 containing ajvalve 22 to the trailingleg 8 of the U-tube, and the region surrounding4 Y i is largest betweenv these two pipes. ...For

maximum flow conditions, either the-iconnection pipes 19and 23, 01-'21 and-23, are used dependent on the 'relative diameters of the pipe 5 and the two straight sectionsli and 17. For intermediate -flow `conditions, the connection pipes not ,used for either the maximum or minimum fiow. conditions are used. That is, pipes' 19 .and 21 for a given flow givev the greatest. pressure difference and if, for instance,pipes 19 and 23 are found to givethe minimum pressure difference with the given flow, then pipes 21 l and 23 Will give an intermediate pressure difference with the given flow.

I thus obtain maximum liquid deflection with three different ratesof ew whereby I am enabled to measure high, lntermediate and low, with the same degree of accuracy.l

In Fig. 2, I have illustrated a form of 'How tube whereby, I am enabled to'obtain astill greater number of different ranges. In this figure the parts numbered 13a, 14, 15, 16aA and 17a'correspond to the parts-numbered 13, 14, 15, 16 and 17 in Figures 41 and 3. However, the `part 17a is formed as a sleeve which surrounds parts 14, 15a and 16"' in spaced relation to them and at its outer end is provided with a flared portion 25. Surrounding sleeve 17a I may provide still another sleeve 26 provided'with a flared end 27 and as will be clear each additional sleeve provides for an additional V:number of pres# sures ranges. The connection-pipes to the U-tube instrument are indicated at' 28, 29, 30,

31 and 32, and as will be clear by using' different pairs of these pipes a large number of pressure ranges may beobta-ined.

My invention possesses substantial utility .from a practical standpoint in that a fiow nozzle embodying it, having been calibrated initially and its constants determined, can be used then in any installation to which it is adapted without special or further calibration.

In accordance with the provisionsof the patent statutes I have described the principle of operation of my invention, together with' the apparatus which I now 'consider to represent thebest embodiment thereof, but

I desire to have it understood that the vapparatusshown is only illustrative and thatthe invention may be carried out by other means.

lVhat I claim asnew and vdesire to secure by Letters Patent of the United States, is,- l. The combination with a conduit through which a fluid tobe metered Hows anda pressure responsive instrument having a leading side and a trailing side, of a How; tube in the conduit comprising a converging section followed by a straight section which in turn is followed by a flaring sec` tion followed by a straight section, said straight sections having lengths equal substantiallyvto at least one-quarter of their own diameters, and pipes connecting the conduit on the upstream side of the flow tube, the region inside the first vstraight section, and the region outside the second straight section to said pressure responsive v instrument.

2. The combination with a conduit through which a fluid to be metered flows and a pressure responsive instrument having a leading side `and a trailing'side, of a flow tube in the conduit comprising a convergin A section followed by successive straight an flaring sections, said straight sections having lengths equal substantially to at least onequarter of their own diameters, and pipes communicating with regions adjacent to the straight sections and serving to connect such regions to the pressure responsive instru# ment. 3.-.A iiow tube comprising a converging section followed by successive straight" arid 'I flaring sections, said flaring sections diverging at an angle of such small value as always to `conlinjera fluid flowing through the-,flow

tube .and prevent its free expansion', 'and said straight sections having lengths equal substantially to at least one-quarter of theirl .flaring sectionssaid straight sections .having lengths equal' substantially to at least onefourth of their own diameters.

6. A flow tube comprising a converging section followed by successive straight and flaring sections, said straightsections hav-v ing lengths equal to at least-substantially one-fourth of their own diameters, and said flaring sections diverging from the straight section -in advance of it at an angle not greater than five degrees.

7. A flow tube comprising a converging l section followed by a straight section which in turn merges gradually into a flaring section followed by a. straight section, said straight sections being of lengths equal to at least substantially one-fourth of their own diameters.

In witness whereof I have hereunto set l my hand this 16th day of October, 1924-.

CHARLES F. BULLOCK. 

